1. Field of the Invention
The present invention relates to security techniques for preventing terrorism and crimes using explosives.
2. Background Art
The threats of terrorism are increasing worldwide. Recently, production methods of explosives using daily commodities have been widely known, and terrorism and crimes using explosives have become threats in daily lives. In London, synchronized terrorist attacks targeting subways and buses occurred and caused many casualties. Moreover, according to press reports, also in Japan, incidents have occurred, for example, suspects who planned suicide terrorism in commuter trains were arrested.
In order to prevent terrorism and crimes, dangerous substance probing techniques are developed in various countries. For example, in JP2000-28579A, an explosive probing system using a mass spectrometer is described. The vapor leaked from baggage is collected by a sampling probe, and it is ionized by using a negative corona discharge and subjected to detection by using the mass spectrometer, thereby determining the presence or absence of dangerous substances.
In order to prevent dangerous liquid such as gasoline from being brought into, for example, an airplane, liquid detection systems have also been developed. For example, in JP2008-157685A, the weight and the permittivity of the bottle containing liquid are measured; and, if they deviate from reference values, it is determined to be a dangerous substance, and an alarm is activated.